Heretofore, engines employing liquid fuel have been equipped with a motor-powered fuel injection pump to allow the liquid fuel to be injected into a combustion chamber of the engine by means of this motor-powered fuel injection pump.
As a motor-powered fuel injection pump employed for a gasoline engine, there is known one structured as shown in FIG. 5, for example. In the pump shown in FIG. 5, a rotating shaft is supported by bearings fixed to both ends of the motor. An impeller is fixed to one end of the rotating shaft and a gasoline flow passage is formed on outer circumferential surfaces of the impeller and motor. Then, gasoline is boosted by a rotating operation of the impeller to be injected into a combustion chamber, not shown, of the engine.
Whereas gasoline engines are being employed in various places of the world, low-quality gasoline containing organic acid is being employed as fuel for the gasoline engines in some regions. In the case that the low-quality gasoline containing organic acid is used, there has been a problem that the bearing for the motor-powered fuel injection pump becomes eroded by the organic acid.
In order to solve such a problem, Japanese unexamined patent application publication No. 2006-199977, e.g., discloses a bearing for a motor-powered fuel injection pump, which is made from a Cu—Ni-based sintered alloy.